A need exists for a back pressure valve with redundant seals that allows fluid to flow through the back pressure valve in a first direction, and provides a secure fluid-tight engagement in a second direction.
A further need exists for a back pressure valve that provides a double barrier to flow.
A further need exists for a reliable back pressure valve that has moving stems in alignment with each other.
A further need exists for a back pressure valve having a first body piece with a first piston threadably connected to a second body piece with a second piston for controlling flow with a double barrier.
The present embodiments meet these needs.
The present embodiments are detailed below with reference to the listed Figures.